1. Field of the Invention
The present invention relates generally to an apparatus for semiconductor processing. More specifically, the invention relates to a lift pin of a substrate support assembly for manipulating a substrate.
2. Description of the Related Art
Integrated circuits have evolved into complex devices that can include millions of components (e.g., transistors, capacitors and resistors) on a single chip. The evolution of chip designs continually requires faster circuitry and greater circuit densities. The demand for greater circuit densities necessitates a reduction in the dimensions of the integrated circuit components.
As the dimensions of the integrated circuit components are reduced (e.g., sub-micron dimensions), particle contamination becomes an increasing problem. One source of particle generation is the lift pins utilized to space a substrate from a substrate support. The lift pins generally reside in guide holes disposed through the substrate support. The lift pins support the substrate upon their top ends and move through the guide holes to actuate the substrate either up or down. One problem that has been observed is the particle generation attributed to contact between the lift pins and the guide holes as the lift pins move through the guide holes.
Thermal processing is also required in the fabrication of silicon and other semiconductor integrated circuits formed in silicon wafers or other substrates. In some thermal process systems, such as Rapid Thermal Processing (RTP), pulsed laser annealing, and dynamic surface annealing (DSA), the substrate support assembly may be used to transfer heat to the substrate. Conventional lift pins located in the guide holes of the substrate support assembly have difficulty transferring heat to the substrate uniformly. Conventional lift pins transfer heat to the substrate either too fast or too slow generating hot spots and cold spots on the substrate surface. Therefore, there is a need for an improved substrate support assembly for substrate processing.